Knock-Out Plate Fitting w/Hardware - Electro-Galvanized is a flat plate fitting that sits directly on top on the strut channel section. The knock-outs are to be punched out in the field as needed and can be used to run wiring in or out of the channel. This product is most commonly used for lighting in ceiling grids or other electrical applications. Electro-Galvanized Steel should be used in interior applications where conditions are dry, and humidity is low.